Got one next to me which cost less than the base Mac Pro for a better spec:

http://www8.hp.com/us/en/campaigns/workstations/z820.html

The form factor is not important if you're not carrying it around. In fact I'd go as far as saying it's retarded for a workstation class machine. Nothing swappable, nothing replaceable, graphics are shit, max memory is pitiful, no internal disk worth mentioning.

It's a joke. A fucking expensive one designed to get slightly mental people to spend money.